This work studies people living alone in Brazil's eight most populated capital cities. Drawing on 1970, 1980, 1991 and 2000 data from the country's census bureau (IBGE), it analyzes demographic and socioeconomic segmentation variables (gender, age range, literacy level and ownership of residence). An increase in loneperson households was observed in comparison to the overall population. Some general trends were also identified, such as the growing participation of people over the age of sixty, retirees and the predominance of women. Besides that, substantial differences were found among the eight cities. Grouping such data may provide support not only for several activity sectors, such as industry, retail and services, but also for issues related to urban planning, architecture, public administration and environment management.